IGB uses approximately 25% of the computer's available RAM by default. This means that when IGB runs on a machine with 4 GB of memory (RAM), it will use 1 GB, or if IGB starts on a machine with 16 GB of RAM, it will use around 4 GB of memory. You can see how much memory IGB is using by looking at the lower-right corner of the IGB window, as seen below.

Changing IGB's available memory

There is a vmoptions file in your IGB installation directory which contains a commented-out jvm argument that sets the max heap size, which is the amount of memory IGB uses.

On Mac the file is located at /Applications/Integrated Genome Browser/IntegratedGenomeBrowser.app/Contents/vmoptions.txt

On Windows the file is located at ${IGB_INSTALLATION_DIR}/IntegratedGenomeBrowser.vmoptions, where $IGB_INSTALLATION_DIR is the folder where IGB resides.

On Linux the file is located at ${IGB_INSTALLATION_DIR}/IntegratedGenomeBrowser.vmoptions, where $IGB_INSTALLATION_DIR is the folder where IGB resides.

To change the heap size, un-comment the jvm argument in line 3 by deleting the hashtag (#) and replace the number on line 3 to the desired heap size. Replacing the number with the value of "2000", for example, would set the heap size to 2 GB so that IGB can use 2 GB of memory. After changing the available memory, save your changes to the vmoptions file and restart IGB to use the new heap size.